<!DOCTYPE html>
<html>

<head>
  <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
  <title>string对象 </title>
  <script type="text/javascript">
    var mystr = "Hello World!"
    document.write(mystr.indexOf('o', mystr.indexOf('o') + 1));
  </script>
</head>

<body>
</body>

</html>